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| Registros recuperados: 1.958 | |
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| Nuthall, Peter L.. |
| In multi-period farm planning problems involving uncertainty, the usual case in the real world, planning must involve a continuous process of re-evaluation. In this dynamic situation it is necessary to know the number of periods to include in the decision model to ensure optimality. This is referred to as the planning horizon. In practice, planning models used are frequently simplifications of reality so the ability to determine the planning horizon under a range of situations is an important facet of planning. This paper contains a survey of methods of determining the horizon and offers comments on the approach necessary to resolve the cases for which methods have not been developed. |
| Tipo: Journal Article |
Palavras-chave: Agribusiness; Farm Management. |
| Ano: 1980 |
URL: http://purl.umn.edu/12575 |
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| John,T. V.St.. |
| Abstract A survey of mycorrhizal infection and depth of rootlets was carried out on a hectare of primary rain forest in which all individuals over 15 cm in diameter had been identified and labeled. Non-mycorrhizal, lightly infected, moderately infected, and heavily infected species made up 16.7, 23.2, 14.8, and 16.7%, respectively, of the total plot's ecological importance value. Of the plot's total importance value, 59.9% were found to have fine roots in the 0- to 10-cm depth range, 7%. to be in the 10-to 30-cm range, and 7.9% to have roots deeper than 30 cm. A strong association was found between root depth and mycorrhizal condition, with surface roots much more likely to be infected than deep roots. Rootlet depth was shown to be a consistent trait... |
| Ano: 1980 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59671980000300527 |
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| Sleumer, H.. |
| In the present work details are given in the first place for the Malesian Olacaceae, representing the basis of my forthcoming treatment of the family in ‘Flora Malesiana’, in which full descriptions of the Malesian genera and species will be given. As the Olacaceae of Malesia are connected with those of South and Southeast Asia on the one, and those of Australia and the Pacific on the other side, it has been necessary to study the respective materials too. A part of the Malesian genera is represented also in Africa inch Madagascar, and even in Central and South America; the appertaining species have been studied but are not mentioned in this paper. A critical elaboration of the family for Africa and America is urgently needed, but will, as far as can be... |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/524792 |
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| Conn, Barry J.. |
| A taxonomic revision of Geniostoma subg. Geniostoma is presented. The relationship between Labordia and Geniostoma is discussed; Labordia being regarded as a subgenus of Geniostoma. General chapters on morphology, anatomy, seed dispersal, chromosome numbers, inter- and intraspecific relationships, geography, and evolution precede the systematic treatment. Two sections are recognised in the subgenus Geniostoma. Section Macrostipulare is described as new. Two sections (sect. Labordia and sect. Darbolia) are recognised in the subgenus Labordia. Section Rabdolia is reduced to the synonymy of section Labordia. Twenty-three species of Geniostoma subgenus Geniostoma are recognised, of which five are described for the first time. The new species are G.... |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/525473 |
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| Croft, J.R.. |
| In this revision 4 endemic species, one with two varieties, are recognized from the alpine and subalpine regions of New Guinea. Isoetes stevensii Croft, I. hopei Croft, and I. neoguineensis Baker var. rheophila Croft are described as new. Scanning electron micrographs of the megaspores and microspores, which furnish important diagnostic characters, are presented for all the taxa in Papuasia as well as for the possibly related species, I. philippinensis Alston. |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/525960 |
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| Ietswaart, J.H.. |
| The present study deals with the systematics and taxonomy of the genus Origanum (Labiatae, Saturejeae). As this difficult genus was never before monographed, a revisional study was much needed. The data presented are mainly based on the study of herbarium specimens and in some cases of living ones. The picture was completed, as far as possible, with data from various literature sources. A short survey is given of the taxonomic history of Origanum, which goes back as far as Linnaeus, and shows that genus and species concepts of various authors have much differed. A morphological outline of Origanum is given, from which it can be concluded that most generic characters are rather variable. Origanum is characterized in the following ways. Medium sized,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/508224 |
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| Water, Th.P.M. van de. |
| In the present revision of Sabia the number of species has been reduced from 55 to 19, including two that are described as new. Below the specific level, a new subspecies and a new variety are described, whereas some new infraspecific combinations have been made. Most of the reduced species have been included in the synonymy of S. campanulata, which consequently represents the most complex and most variable species of the genus. Next to a general key, some regional keys are given as on the one hand some widespread species are locally far less variable than taken over their whole area, on the other hand well-delimited species from different regions may be very uniform in some points. |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/525283 |
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| Trueba, Frank J.. |
| This paper is a critical revision of the protozoan genera Thuricola and Psendothuricola (Ciliata, Peritrichia, Vaginicolidae). Thuricola Kent, 1881, is considered to include the nominal genus Thuricolopsis Stokes, 1887, but it is kept apart from Pseudothuricola Kahl, 1935. An annotated list of the hitherto described nominal species is given. Eleven species are recognized within the genus. A short description of each of these and a key to their identification are given. All recognized species are figured; some illustrations from the literature have been redrawn and brought together to facilitate comparison among them and to justify the taxonomical decisions which have been taken. |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/504890 |
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| Prance,Ghillean T.. |
| Resumo Há muita confusão na literatura botânica sobre a terminologia empregada para os tipos de mata inundada temporária ou permanentemente. É necessário criar uma terminologia mais correta em termos de cobertura vegetacional, tipo de água e duração da alagação. No Brasil, os termos várzea e igapó e Tahuampa, no Peru, têm sido atribuídos a tipos muito diferentes de mata pelos ecologistas e cientistas de outras disciplinas e até agora não têm definição correta. Neste trabalho, é tentado classificar as categorias principais de vegetação inundável. |
| Ano: 1980 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59671980000300499 |
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| Martin, Jocelyne. |
| Within the framework of the ecological study related to the construction of a coastal nuclear power plant in Flamanville (westcoast of Cotentin, English Channel), zooplancton was sampled in the vicinity from april 1977 to september 1979 according to a monthly and even fortinghtly frequency. This paper presents the results obtained about the larvae of three commercial brachyuran decapoda species : the Velvet Swiming crab (Macropipus puber, L.), the Spinous Spider Crab (Maia squinado Herbst) and the Edible Crab (Cancer pagurus, L.). For the three annual cycles considered saisonal variations in abundance of zoeal and megalopa stages were represented. For the 1978 and 1979 samples we made, in addition, the distinction between the successive zoeal stages.... |
| Tipo: Text |
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| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/acte-3918.pdf |
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| Otero, H.O.. |
| The statistics provided by the Argentinean Fishing Vessel and the biological data collected by scientist in the last eleven years, allow us to estimate different aspects of the population dynamics of the common hake (Merluccius hubbsi). This work deals with the relative abundance and the maximal sustainable yield of this species, considering the bonaerense stock of the Southewest Atlantic. Analyzing the effective fishing density, concluding remarks can be made. The high catches of 1967 (more than 600.000 tons.)made by the Russian Fleet, affected the fishing density in 1968. Since 1969, the resource recovered the high density level as a consequence of a decrease in the catches and in the fishing effort, but vulnerability of the stock is shown. |
| Tipo: Journal Contribution |
Palavras-chave: Catch/effort; Potential yield; Hake fisheries. |
| Ano: 1980 |
URL: http://hdl.handle.net/1834/2061 |
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| Otero, H.O.. |
| The statistics provided by the Argentinean Fishing Vessel and the biological data collected by scientist in the last eleven years, allow us to estimate different aspects of the population dynamics of the common hake (Merluccius hubbsi). This work deals with the relative abundance and the maximal sustainable yield of this species, considering the bonaerense stock of the Southewest Atlantic. Analyzing the effective fishing density, concluding remarks can be made. The high catches of 1967 (more than 600.000 tons.)made by the Russian Fleet, affected the fishing density in 1968. Since 1969, the resource recovered the high density level as a consequence of a decrease in the catches and in the fishing effort, but vulnerability of the stock is shown. |
| Tipo: Journal Contribution |
Palavras-chave: Catch/effort; Potential yield; Hake fisheries. |
| Ano: 1980 |
URL: http://hdl.handle.net/1834/5456 |
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| Castro,Paulo R.C.. |
| Determinou-se em condições de casa de vegetação o efeito de fitoreguladores no potencial osmótico foliar da soja. As aplicações das substâncias de crescimento foram realizadas 21 dias após a semeadura. Efetuou-se pulverização de cloreto (2 -cloroetil) trimetilamônio (CCC) 2.000 ppm, ácido succínico-2,2-dimetilhidrazida (SADH) 4.000 ppm, ácido giberélico (GA) 100 ppm, ácido indolilacético (IAA) 100 ppm, além do controle. O potencial osmótico foliar foi determinado durante três dias em intervalos de 24 horas. Utilizou-se o delineamento inteiramente casualizado com 4 repetições e procedeu-se à comparação de médias pelo teste Tukey (57o). Os resultados obtidos pelo método osmométrico mostraram que plantas tratadas com fitoreguladores apresentam variação no... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1980 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761980000200016 |
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| Castro,Paulo R.C.; Gutierrez,Luiz E.. |
| Em condições de casa de vegetação, estudou-se o efeito de fitoreguladores nos teores de carboidratos solúveis totais, sacarose, glucose, frutose e fenóis totais nas folhas da planta de soja 'Davis'. Pulverização com cloreto (2-cloroetil) trimetilamonio (CCC) 2.000 ppm, ácido succínico-2,2-dimetilhidrazida (SADH) 4.000 ppm, ácido giberelico (GA) 100 ppm e ácido indolilacético (IAA) 100 ppm foi efetuada 25 dias após a semeadura. Coletando-se as folhas 43 dias após a semeadura, realizou-se a extração dos carboidratos e determinação usando-se glucose como padrão. A separação dos açúcares foi efetuada por cromatografia de papel e a quantificação pelo método de Dubois. Após a extração dos fenóis procedeu-se à determinação adotando-se catecol como padrão.... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1980 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0071-12761980000200017 |
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| Registros recuperados: 1.958 | |
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